The present invention relates to electrical junction boxes and in particular to an improved mounting system for such a box.
Heretofore, electrical junction boxes have conventionally been formed with a plurality of external lugs provided at various locations and/or internal weakened sections defining a "knockout" which could readily be removed. In use, an installer knocks out the weakened section of the lug in the field and then passes a fastener through the resulting opening to secure the box in place. Since the box must be capable of being mounted to a wide variety of surfaces with different types of fasteners, the resultant opening must be sufficiently large to accommodate the largest fastener that may be used.
In many applications the above presents a problem in that the opening may be sufficiently larger than the fastener to permit moisture to enter into the junction box. This poses a special problem where the box is used out of doors.
In view of the above, it is the principal object of the present invention to provide an improved junction box construction wherein the mounting openings are designed to engage an associated fastener in a moisture-tight fit regardless of the size of the fastener.
A further object of this invention is to provide a device which is relatively easy to manufacture, can accommodate a wide range of fasteners, and which may readily and easily be mounted to all types of wall surfaces.
A further object of this invention is to eliminate the need for external mounting lugs so that boxes can be mounted close together and the cost of the lugs is eliminated.